Method and apparatus for generating steam, especially high-pressure steam



S. LUFFLER METHOD AND APPARATUS FOR GENERATING STEAM,

Dec. 17, 1929.

ESPECIALLY HIGH PRESSURE STEAM Filed March 25, 1924 hereinafter.

#Patented Dec. 17, 1925 UNITED STATES PATENT OFFICE STEPHAN LoFFLER, or

METHOD AND APPARATUS non CHARLOTTENBURG, NEAR BERLIN, GERMAN GENERATING STEAM, ESPECIALLY HIGH-PRESSURE STEAM Application filed March 25, 1924, Serial No.

eration of such steam is connected with very as the material of the boiler great difficulties is subjected to an extraordinarily dangerous strain resulting fromthe high pressure and the high temperature, if the heat of the fire in the furnace is transmitted to the water through the boiler-walls. As the heat of the fire-gases can rise to 1000 C. and more, dangerous local accumulations of heat in the boiler-walls cannot be obviated, especially if there exists sediments of scale, mud, or the like in the boiler. v

My invention relates to an improved method of producing steam, especially steam of very high pressure (for instance a pressure exceeding 50 atm.), and the gist of this invention resides in transmitting the heat to the water not through the boiler-walls, i. e. indirectly, but directly, as is fully described Generally, .my improved method consists in introducing superheated steam into a fire- 5 less boiler,and in evaporating the boiler water'solely by said steam. More particularly, the invention consists in withdrawing continuously a part of the steam generated in the fireless boiler, converting said part 0 into superheated steam, and introducing this steam into the boiler water in order to evaporate it .thereby. The steam withdrawn from the boiler is converted into superheated steam in a separate heating device which is independent of, and may be remote from, the boiler.

The steam withdrawn from the boiler is withdrawn in a positive manner by means of a pump or the like, and the separate heatingdevice may consist of a flue or flues enclosing a coiled pipe or coiled pipes. The entire amount of this steam is then introduced into the boiler water for the purpose stated. I,

That steam which is to be consumed in an engine is tapped either from the steam space of the fireless boiler or from the pipe which connects the separate superheater with said boiler, that is to say, which conducts the superheated steam generated outside the fireless by side, or one above or below the other,

boiler is effected by the feed-pump 701,855, and in Germany October 6, 1923.

boiler into this latter in order to generate high pressure steam therein.

The fireless boiler and the separate evaporator and superheater may be arranged in any relation with respect to one another, 1. e. side and they may be located remote from each other for a certain distance, as the case may be.

In the accompanying drawings: Figure 1 is a sectional view through the main boiler,

auziiliary boiler furnace and pumps and illustrating the pipe connections therebetween and Figure 2 is a .detail sectional View of the main boiler showing a slightly modified arrangement of pipe connections wherein the supply of steam may be fed from the boiler.

In Figure 1, K denotes a boiler, and ss the level of the water within it. The water is fed into the boiler in preheated state with a temperature approximating that at which the conversion into steam takes place. Feeding the thus far pre-heated water into the S which receives the water through the pipe m and delivers it through the pipe 72..

G denotes a furnace, the fire-space F of which is furnished with an endless or travelling grate R. There are in the furnace G three chambers H H H contains a coiled tube 0 the second a coiled tube 0 and the third a coiled tube 0 The fire gases pass through the three chambers, which are arranged in series, and wash the coils in the same order. The coil 0 is con nected at its 11 per end with the feed ump 8,, by means 0 the pipe at, and at its ower end with the water space of the boiler K by means of the pipe n which terminates at a: with the steam-space of the boiler by means of the pipe I), and at its lower end with a pipe 6 through which the steam can be conducted to an engine. or the like in order to be utilized. The coil 0 is connected at its upper end with the circulation pump U by means of the pipe 0 and at its lower end with the perforated distribution pipe by means of the pipe (1 which is connected at d with said pipe 11 of which the first The coil 0 is connected at its upper end r the steam is withdrawn through the pipe up to boiler-temperature without generation c and caused to flow through the coil 0 with the aid ofthe circulation pump U superheated in this coil (from which it gets back to the boiler through the pipe al and is introduced directly into the boiler-water by means of the perforated pipe 10 and divided into two currents, one being that passing through the pipe 0 to the pump U the other being conducted through the pipe I; to

the coil 0 in which it is also superheated in a certain degree, although less than the steam passing through the coil 0 The steam is then conducted to the place or places of use through the pipe 6, as already mentioned.

In order to heat the feed-water practically of steam in the conduit from the feed-pump to the boiler, this pump may exert on'the water in said conduit a pressure which is above the boiler-pressure, a reduction of the pressure being then effected immediately before the water enters into the boiler.

An auxiliary boiler or water-heater with a furnace of its own may be provided, or combined with the arrangement and combination shown in the drawing, for the purpose of heating a part of the water and convert it into steam of moderate pressure in order to initiate the operation of the steam-producing plant. When service-pressure has been reached, that additional boiler and furnace are thrown out of action. That part of the boiler-water, or the separate additional or auxiliary boiler respectively, may be heated electrically, if desired. I I

Starting the heating of the high pressure steam generator may be effected for instance by means of a separate auxiliary boiler such as a plain-tube boiler or the like. as shown by way of example in Figure 1 which may be fired with coal, oil or gas or any othen suitable fuel. This boiler can stand a ressure of about fifteen centimeters an its waste gases may either escape directly through the chimney or may be conducted prior thereto through the heating-device of the high pressure steam generator. The low pressure steam produced in the boiler 15 is conducted into the coiled tube 0 of the high pressure plant and into the steam distributing tubev p in order to heat the water contained in the boiler K; and to initiate the gen eration of steam in the same. When finally the pressure in the boiler K has arisen so as to'be' equal to that in the boiler t, the communication between the boilers isinterrupted by the shut off valve 4) which may be operpressure.

ated either manually or automatically and may be designed as a non-return valve.. The further heating of the high pressure boiler is then efiected in the manner already described Without any other particular auxiliary means.

It is also possible to withdraw the superheatedliv e' steam from the pipe 03 which connects the superheating coil 0 with the perforated pipe F. It is then necessary to provide a branch pipe 03 (Fig. 2) and it is suited to the purpose to insert a valve 03 into this pipe through which the superheated steam is conducted to the engine.

The improved steam-generation method disclosed in the preceding pages renders possible a very reliable operation of the steamproducing plant, as well as secure service. An incrustation of the boiler-walls, or ac-- cumulation of mud etc. in the boiler, is of no detrimental influence 011 the operation of the boiler and on the generation of the steam. In the contrary, losses of heat by. radiation are prevented, and it is, besides,vpossible to provide the boiler K with an outer protective covering or lagging. But it is also possible to heat the boiler a little from without merely in order to prevent securely losses by radiation. The boiler is also less sensitive; as regards variations of the height of the level of the liquid, in contradistinction to boilers with outer heating. The pipes by which the heat in the heater or superheater O is transmitted to the steam or to the water streaming through them are only of small diameter and can be manufactured so as to be perfectly reliable and safe in service also at a very high No inadmissible accumulation of heat in the walls of these pipes can occur as the fluid is driven positively or compulsorily through them by the pump U I claim:' p

1. The method of generating high pressure steam i. e., steam of a pressure exceeding 735 lbs. per square inch (50 atmospheres),

consisting in heating water indirectly to gen-' erate steam, withdrawing continuously a part of the steam thus generated, increasing the pressure of the part of the steam so with-. drawn, superheating the part ofthe steam so withdrawn and compressed, and introducing said superheated steam into the water.

2. A high pressuresteam generating apparatus comprising a fireless boiler, means communicating with the steam space of said boiler for wlthdr'awing steam n generated within the latter, a superheater for superheating the withdrawn steam, and means for introducing the superheated steam into the boiler.

3. A high pressure steam generating ap-- paratus comprising va fireless boiler, means communicating-with the steam space of the boiler for withdrawing and super-heating the steam generated in the boiler, said means having communication with the water space of the boiler for introducing the superheated steam into the latter.

4. A high pressure steam generating apparatus comprising a tireless boiler, means communicating with the steam space of the boiler, for withdrawing and superheatin the steam generated in the boiler and adapte to force the thus generated steam into the Water space of the boiler, and an independent steam supply means for said boiler having controllable communication therewith.

5. A high pressure steam generating ap-- paratus comprising a fireless boiler, means communicating With the steam space of the fireless boiler, for Withdrawing and superheating the steam generated in the said fireless boiler and adapted to force the thus superheated steam into the Water space of the fireless boiler, an independently heated boiler having communication with said fireless boiler for supplying the latter With additional steam, and means for intercepting communication between the. said boilers. 25 In testimony whereof I aflix my signature.

STEPHAN LOFFLER. 

